SMASH Study: Spatial Molecular Atlas of chronic Subdural Hematomas - Chronic subdural hematomas (cSDH) are one of the most common neurosurgical conditions in the United States. cSDH is a progressive hemorrhage in the subdural space between the dura and the arachnoid mater. The bleed is characteristically encased by a neomembrane made of a dura-mater-facing outer membrane (OM) and an arachnoid-mater-facing inner membrane (IM). These neomembranes have been implicated in the continued pathology and recurrence of the condition. It is hypothesized that damage to dural border cells and subsequent pro-inflammatory and pro-angiogenic signaling cascades can exacerbate neomembrane growth. However, little has been reported on the cellular and molecular architecture of the tissue or its exact role in cSDH pathophysiology. The overall goal of this proposal is to develop an understanding of the cellular and molecular pathogenesis of chronic subdural hematomas. My goal is to address the following questions: What cells are the membranes made of, and how are they distributed? What are the molecular changes across different regions of the tissues? Are there novel markers that correlate with cellular diversity or disease severity? I hypothesize that the molecular characterization of neomembranes will identify key markers associated with angiogenesis, pro-inflammation, and fibroproliferation that will correlate with cSDH severity. AIM 1) In the total cohort of 31 patients, I will stage cSDH disease severity of patients by collecting clinical and radiographical outcomes (AIM 1A); identify cellular and morphological diversity through immunohistochemistry (AIM 1B); and characterize protein and genetic diversity through immunofluorescence staining and bulk RNA sequencing (AIM 1C). AIM 2) Next, I will characterize the spatial transcriptome and proteome across the neomembranes via NanoString GeoMx Digital Spatial Profiler (DSP) and correlate the spatially resolved – omics datasets to the patients’ clinical and radiographical databases (AIM 2A), and then will validate the most enriched gene and protein signatures using a variety of molecular techniques (AIM 2B). Our preliminary data shows a distinct distribution of cells and proteins across the outer membrane. Dura-facing sides have a highly vascular area, intermediate layers consist of acellular or sinusoidal cellular regions, and hematoma-facing sides have high cell densities. These cell densities include large lymphocytic and eosinophilic infiltrates. Further molecular characterization is required. I expect that I will be able to subtype cSDH into different stages of the disease through the creation of transcriptomic and proteomic spatial atlases in this study. I aim to identify key insights on cSDH pathophysiology by identifying factors associated with angiogenic and pro-inflammatory cascades in cSDH. This study is significant because it will generate novel molecular information on cSDH. The use of the Nanostring GeoMx DSP to create whole transcriptomics and proteomics atlases is highly innovative. This study will help identify markers of interest that can serve as therapeutic targets for improving cSDH intervention and cSDH staging and give key insights on pathogenesis that have not yet been reported.
